The subject matter disclosed herein relates generally to underground cables and, more particularly, to a system and device for detecting defects in underground cables.
Underground cables enable electricity to travel from a power plant to residential and commercial customers. The cables include conductors where the electric current flows, and insulation that surrounds the conductors to inhibit the electric current from flowing outside the conductors. The cable insulation may deteriorate over time and become faulty, causing defects such as water trees and electrical trees in the insulation. A partial discharge refers to an abrupt change in current in the cable that may be generated during the breakdown of insulation or when arcs happen the cable and another insulator. Protracted partial discharge may further erode the cable insulation and result in a total breakdown of insulation, or complete cable failure.
Monitoring the underground cables to detect insulation defects using partial discharge analysis may be desirable in order to prevent a total breakdown of insulation or complete cable failure. When cables are monitored, a defect may be found early, such as before a complete breakdown occurs. The cable may be repaired or replaced to eliminate defects. Some monitoring systems perform monitoring based on a cable maintenance schedule. However, a monitoring system or device may provide quicker results if the underground cables are continuously monitored. Such a system enables a condition based monitoring which may improve efficiency and decrease cost. Thus, a need exists for a system or device that can continuously monitor for defects in underground cables.